High temperature high pressure (HTHP) cell in sum frequency generation (SFG) spectroscopy for oil/brine interface analysis with reservoir conditions and dynamic compositions

ABSTRACT

A pressure cell for sum frequency generation spectroscopy includes: a metal pressure chamber; a heating stage that heats a liquid sample; an ultrasonic stage that emulsifies the liquid sample; a chamber pump that pressurizes an interior of the metal pressure chamber; and a controller that controls the chamber pump, the ultrasonic stage, and the heating stage to control a pressure of the interior of the metal pressure chamber, an emulsification of the liquid sample, and a temperature of the liquid sample, respectively. The metal pressure chamber includes: a liquid sample holder that retains the liquid sample; a removable lid that seals against a base; a window in the removable lid; a sample inlet that flows the liquid sample from an exterior of the metal pressure chamber to the liquid sample holder at a predetermined flow rate; and a sample outlet.

BACKGROUND

Water injection is a common technique used in oil production to increasethe yield of hydrocarbons from a reservoir. The interactions between thevarious phases in the reservoir (e.g., oil, water, brines, calcite rock,and gas) can greatly affect yield of the recovered hydrocarbons. Forexample, by controlling the salinity and the ionic strength of theinjected solution, the wettability of rock formations in the reservoircan be changed to improve recovery. To further improve the yield ofhydrocarbons, various spectroscopic techniques such as SFG spectroscopyhave been used to understand the nature of the interactions between thephases in the reservoir and characterize the chemical and molecularstructure and interfaces of the phases.

SUMMARY

In one aspect, one or more embodiments disclosed herein relate to apressure cell for SFG spectroscopy. The pressure cell includes a metalpressure chamber that includes a liquid sample holder that retains aliquid sample, a removable lid that seals against a base to enclose theliquid sample holder in an interior of the metal pressure chamber, awindow in the removable lid that allows the liquid sample to beoptically accessed from an exterior of the metal pressure chamber, asample inlet that flows the liquid sample from the exterior of the metalpressure chamber to the liquid sample holder in the interior of themetal pressure chamber at a predetermined flow rate, and a sample outletthat flows the liquid sample from the liquid sample holder to theexterior of the metal pressure chamber. The pressure cell furtherincludes: a heating stage, disposed in the interior of the metalpressure chamber, that heats the liquid sample; an ultrasonic stage,disposed in the interior of the metal pressure chamber, that emulsifiesthe liquid sample; a chamber pump, connected to the interior of themetal pressure chamber, that pressurizes the interior of the metalpressure chamber; and a controller that controls the chamber pump, theultrasonic stage, and the heating stage to control a pressure of theinterior of the metal pressure chamber, an emulsification of the liquidsample, and a temperature of the liquid sample, respectively.

In another aspect, one or more embodiments disclosed herein relate to asystem for performing SFG spectroscopy. The system includes: a pressurecell and a sum frequency generation microscope. The pressure cellincludes a metal pressure chamber that includes a liquid sample holderthat retains a liquid sample, a removable lid that seals against a baseto enclose the liquid sample holder in an interior of the metal pressurechamber, a window in the removable lid that allows the liquid sample tobe optically accessed from an exterior of the metal pressure chamber, asample inlet that flows the liquid sample from the exterior of the metalpressure chamber to the liquid sample holder in the interior of themetal pressure chamber at a predetermined flow rate, and a sample outletthat flows the liquid sample from the liquid sample holder to theexterior of the metal pressure chamber. The pressure cell furtherincludes: a heating stage, disposed in the interior of the metalpressure chamber, that heats the liquid sample; an ultrasonic stage,disposed in the interior of the metal pressure chamber, that emulsifiesthe liquid sample; a chamber pump, connected to the interior of themetal pressure chamber, that pressurizes the interior of the metalpressure chamber; and a controller that controls the chamber pump, theultrasonic stage, and the heating stage to control a pressure of theinterior of the metal pressure chamber, an emulsification of the liquidsample, and a temperature of the liquid sample, respectively. The sumfrequency generation microscope includes: a first light source thatgenerates light of a first variable frequency; a second light sourcethat generates light of a second frequency; and a detector that detectslight.

In another aspect, one or more embodiments disclosed herein relate to amethod of performing SFG spectroscopy. The method includes: sealing aliquid sample holder in an interior of a metal pressure chamber thatincludes a base and a removable lid; flowing a liquid sample from anexterior of the metal pressure chamber, thorough a sample inlet, to theliquid sample holder in the interior of the metal pressure chamber at apredetermined flow rate; emulsifying the liquid sample with anultrasonic stage; heating the liquid sample with a heating stage;pressurizing the interior of the metal pressure chamber with a chamberpump that is connected to the interior of the metal pressure chamber;illuminating a surface of the liquid sample with light of a firstvariable frequency and light of a second frequency through a window ofthe metal pressure chamber; collecting, through the window, light of athird frequency that is the sum of the first variable frequency and thesecond frequency from the surface of the liquid sample; and flowing theliquid sample from the liquid sample holder, through a sample outlet, tothe exterior of the metal pressure chamber.

Other aspects and advantages will be apparent from the followingdescription and the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A shows an oil and gas production facility.

FIG. 1B shows a schematic of a sum frequency generation system.

FIG. 2 shows an open pressure cell for SFG spectroscopy according to oneor more embodiments.

FIG. 3 shows a sealed pressure cell for SFG spectroscopy according toone or more embodiments.

FIG. 4 shows a schematic of a controller according to one or moreembodiments.

FIG. 5 shows a system for performing SFG spectroscopy according to oneor more embodiments.

FIGS. 6A and 6B show a method for performing SFG spectroscopy accordingto one or more embodiments.

DETAILED DESCRIPTION

Specific embodiments of the present disclosure will now be described indetail with reference to the accompanying figures. Like elements in thevarious figures are denoted by like reference numerals for consistency.

Numerous specific details are set forth in the following detaileddescription in order to provide a more thorough understanding ofembodiments of the present disclosure. However, it will be apparent toone of ordinary skill in the art that the present disclosure may bepracticed without these specific details. In other instances, well-knownfeatures have not been described in detail to avoid unnecessarilycomplicating the description.

Throughout the application, ordinal numbers (e.g., first, second, third,etc.) may be used as an adjective for an element (i.e., any noun in theapplication). The use of ordinal numbers is not to imply or create aparticular ordering of the elements nor to limit any element to beingonly a single element unless expressly disclosed, such as by the use ofthe terms “before,” “after,” “single,” and other such terminology.Rather the use of ordinal numbers is to distinguish between theelements. By way of an example, a first element is distinct from asecond element, and the first element may encompass more than oneelement and succeed (or precede) the second element in an ordering ofelements.

In general, embodiments disclosed herein provide an apparatus, a system,and a method for performing sum frequency generation (SFG) spectroscopyunder simulated reservoir and dynamic conditions to characterize themolecular and chemical structures and interfaces of an oil/brine sample.For example, as shown in FIG. 1 , an oil production facility 100 locatedabove a hydrocarbon reservoir 102 may include an oil rig 104 and an oilwell 106 to extract hydrocarbons 108. The hydrocarbons 108 may beextracted by pressurizing the reservoir 102 with an injection solution(e.g., conventional water injection, specialized aqueous solutioninjection) from a second well (not shown).

To improve the effectiveness of the injection recovery technique, themicroscopic characteristics of, and interactions between, thehydrocarbons 108, the injection solution, and the rock formations of thereservoir 102 may be studied. Examples of such interactions may includesurface charge interaction, ionic exchange, and rock dissolution. SFGspectroscopy may be used to probe the fluid/fluid or fluid/rockinteractions and to characterize the chemical and molecular structuresand interfaces of a liquid sample, discussed in further detail below.Accordingly, one or more embodiments disclosed herein relate to anapparatus, a system, and a method of studying a liquid sample with SFGspectroscopy in a simulated high temperature and high pressure reservoirenvironment. Alternatively, other optical techniques (e.g., differencefrequency generation (DFG) spectroscopy, Raman spectroscopy) may be usedin conjunction with embodiments disclosed herein.

In one or more embodiments, a liquid sample may be extracted from asubsurface facility (e.g., the reservoir 102). For example, a live oilsample may be obtained from the oil well 106. Furthermore, to moreclosely recreate the actual fluids found downhole in the well (e.g.,compositions previously determined using a modular formation dynamictester (MDT) technique), gases such as gaseous hydrocarbons, hydrogensulfide, and the like may be remixed into the live oil sample.Alternatively, or in addition, aqueous solutions may be remixed into thelive oil sample to recreate the actual fluids found downhole in thewell, as described below.

In one or more embodiments, liquid samples collected from the reservoirmay be separated into two phases: an organic phase (i.e., primarilyhydrocarbons 108 of the live oil sample) and the second componentincludes an aqueous phase (i.e., primarily water). Then, the two phasesmay be remixed with a predetermined ratio and/or predetermine level ofemulsification. Thus, the liquid sample to be studied may be a syntheticbrine (i.e., prepared in a laboratory) comprising the remixedhydrocarbons 108 and an aqueous solution.

The term “brine” is defined as a mixture comprising two or moreimmiscible liquids. A first component of the brine is dispersed in asecond component of the brine. In one or more embodiments, the dispersedfirst component includes an organic phase (i.e., primarily hydrocarbons)and the second component includes an aqueous phase (i.e., primarilywater). Alternatively, the phases of the first and second components maybe reversed. In one or more embodiments, the liquid sample may be abrine comprising gaseous hydrocarbons, liquid hydrocarbons, solidhydrocarbons, salts, metals, impurities, water, an aqueous solution, andany combination thereof.

FIG. 1B shows a schematic of a sum frequency generation system. In sumfrequency generation, a sample is probed with two incident light beamsthat overlap in space (i.e., both beams converge at a coincidence pointon the sample) and time (i.e., the pulses from both beams are incidenton the sample at the same time). The size of the coincidence point thatis probed corresponds to the spot size of the two incident light beamswhich may be around 150 microns in diameter.

The first light beam is centered at a first variable frequency f₁ thatmay correspond with an energy level of a molecular vibrational mode thatoccurs in the sample (e.g., corresponds to an infrared wavelength oflight). The first variable frequency f₁ may be continuously ordiscretely changed (e.g., with a tunable light source, a filtered lightsource, a spectrometer, or the like) to probe different energy levels ofdifferent molecular vibrational modes in the sample. The first lightbeam may be incident at an angle of 60° with respect to the normalvector of the sample surface.

The second light beam is centered at a second frequency f₂ that isdifferent from the first variable frequency f₁ and may correspond to avirtual energy state (e.g., corresponds to a visible wavelength oflight). The second light beam may be incident at an angle of 55° withrespect to the normal vector of the sample surface. After absorbing thetwo coincident light pulses, non-linear effects induced by thenon-linear susceptibility of the sample causes the surface of the sampleto emit light of a third frequency f₃ that is the sum of the first andsecond frequencies f₁, f₂ (i.e., an SFG signal).

In one or more embodiments, an SFG spectrum is generated by scanning thefirst variable frequency f₁ across a range of frequencies that span anenergy level of a molecular vibrational mode of interest. When the firstvariable frequency f₁ corresponds to the energy level of the molecularvibrational mode, the intensity of the emitted SFG light at the thirdfrequency f₃ will increase due to a resonant effect of the first lightbeam exciting the molecular vibrational mode. By analyzing the intensityof the detected third frequency of light f₃, the vibrational modes inthe sample may be identified from the resonant frequencies. Furthermore,the directional dependence of the non-linear susceptibility of thesample allows a user to derive information about the orientation ofmolecules in the sample from the polarization of the collected SFGsignal.

In one or more embodiments, the first light beam may be a spectrallybroadband light beam that includes a plurality of frequencies f₁ whilethe second light beam remains at a single fixed frequency f₂.Accordingly, the emitted SFG light from the sample would include aplurality of third frequencies f₃ that may be collected simultaneouslyfor faster data acquisition.

FIGS. 2 and 3 show a pressure cell 200 for SFG spectroscopy accordingdifferent embodiments of the present invention. The pressure cell 200simulates conditions that occur in the reservoir 102 (FIG. 1 ). Thepressure cell 200 includes a metal pressure chamber 202 that encloses aliquid sample holder 204 that retains a liquid sample 206 (e.g., abrine). In one or more embodiments, the liquid sample holder 204 mayinclude a rock interface 207 (e.g., a calcite rock sample, a dolomiterock sample, an anhydrite mineral sample, a part of a carbonite rocksample, or any combination thereof) or any other appropriate material tointeract with the liquid sample 206 to further simulate interactionsthat occur in the reservoir 102 (FIG. 1 ).

The metal pressure chamber 202 includes a base 208 and a removable lidthat enclose the liquid sample holder 204 within the metal pressurechamber 202. The base 208 and the removable lid 210 are formed from ametal and may be aluminum, stainless steel, or any other appropriatemetal with sufficient strength to withstand the temperatures andpressures of a simulated reservoir environment. In one or moreembodiments, the metal pressure chamber 202 may have a circularcross-section and a diameter of at least 20 cm. Alternatively, the metalpressure chamber may have a rectangular cross-section. However, themetal pressure chamber 202 is not limited to these shapes or dimensionsand any appropriate size or shape may be used.

As shown in FIG. 2 , in one or more embodiments, the base 208 maycomprise a horizontal base plate 208 a and a vertical wall(s) 208 b thatextends in a direction perpendicular to the base plate 208 a. The baseplate 208 a and wall(s) 208 b define a cavity 208 c that retains theliquid sample holder 204. The base 208 includes an interior surface thatis exposed to the simulated environment created in an interior of themetal pressure chamber 202 and an exterior surface that is exposed to anexternal environment of the metal pressure chamber 202. In one or moreembodiments, the base 208 may further include one or more feedthroughs208 d that communicate between the interior surface and the exteriorsurface of the base 208.

A feedthrough 208 d may be a channel, a port, a fluid path, a length oftubing, an electrical line, an electrical conduit, an electrical plug,or any combination thereof depending on the material or signal beingpassed through the base 208. For example, one or more feedthroughs 208 dmay be electrical conduits that pass signals (e.g., control signals) orpower to equipment inside the metal pressure chamber 202, as describedbelow. In addition, one or more feedthroughs 208 d may include a channelconnected to a chamber pump 230, described below, that pressurizes theinterior of the metal pressure chamber 202. Further still, one or morefeedthroughs 208 d may include various tubes that introduce and removethe liquids sample 206 to and from the interior of the metal pressurechamber 202.

As discussed above, the removable lid 210 cooperates with the base 208to form the metal pressure chamber 202 that encloses the liquid sampleholder 204. The removable lid 210 may be a planar plate that sealsagainst an upper surface of the wall(s) 208 b of the base 208. Theremovable lid 210 may attach to the base 208 by a set of cooperatingthreads (i.e., screws onto the base 208), one or more clips (i.e.,clipped onto the base 208), or by fastening one or more fasteners (e.g.,bolts, screws). However, the removable lid 210 may attach to the base208 by any appropriate means that provides a seal to contain thepressure of the simulated reservoir environment. As shown in FIG. 2 , inone or more embodiments, a seal 212 may be disposed between the base 208and the removable lid 210 to isolate the simulated environment insidethe metal pressure chamber 202 from the external environment of themetal pressure chamber 202. The seal 212 may be an elastomer O-ring, acopper gasket, any other appropriate sealing material, or anycombination thereof.

In one or more embodiments, the removable lid 210 comprises a window 214that allows the liquid sample 206 to be optically accessed from theexterior of the metal pressure chamber 202 (e.g., to allow light from anexternal source to access the liquid sample 206). The window 214 may betransparent to a first, a second, and a third frequency of light (i.e.,frequencies f₁, f₂, and f₃), where the third frequency f₃ is the sum ofthe first and second frequencies f₁, f₂. The window 214 may be made ofglass (e.g., a silica based glass, a calcium fluoride based glass, orthe like) that is transparent enough to allow the liquid sample 206 tobe illuminated with light of the first and second frequencies f₁, f₂from a source disposed outside of the metal pressure chamber 202. Thewindow 214 may also be transparent enough to pass the generated SFGsignal comprising light of the third frequency f₃ from the liquid sample206 to a detector disposed outside of the metal pressure chamber 202.The window 214 may have a refractive index of approximately 1.5. Thewindow 214 may be coated with an antireflection coating.

In one or more embodiments, the window 214 may comprise multipletransparent windows. For example, the removable lid 210 may comprisethree distinct windows 214, wherein the optical properties (e.g.,transmission coefficient) of each window 214 is tuned to a correspondingfirst, second, and third frequency f₁, f₂, f₃ of light, respectively.

In general, the base 208 and the removable lid 210 cooperate to enclosethe liquid sample holder 204 and the window 214 allows external light toaccess the liquid sample 206. However, other embodiments may be devisedwithout departing from the scope of embodiments disclosed herein. Forexample, the base 208 may comprise only a base plate 208 a while thewall(s) that define the cavity 208 c of the metal pressure chamber 202may be disposed on the removable lid 210. In this configuration, thebase 208 may be removable from the lid 210. Accordingly, the one or morefeedthroughs 208 d may be disposed on the lid 210 rather than the base208.

As discussed above, the metal pressure chamber 202 encloses a liquidsample holder 204 that retains the liquid sample 206. The liquid sampleholder 204 may be made of any appropriate material that retains theliquid sample 206. In one or more embodiments, the liquid sample holder204 is made of a non-corrosive material (e.g., a stainless steel, apolymer, TEFLON, or the like) that can be easily cleaned of the liquidsample 206 and reused. For example, the liquid sample holder 204 may bemade of TEFLON which exhibits excellent chemical and temperatureresistance up to 250° C.

The liquid sample holder 204 may be any shape (e.g., circularcross-section, non-circular cross-section) provided that the liquidsample 206 retained by the liquid sample holder 204 is exposed to theinterior of the metal pressure chamber 202. In one or more embodiments,the liquid sample holder 204 may be an open cylinder with a circularcross-section and a diameter of 10-15 cm. The liquid sample holder 204may retain 15-20 mL of the liquid sample 206. However, any appropriatesize or shape may be used to retain the liquid sample 206 provided theliquid sample holder 204 fits within the metal pressure chamber 202.

In one or more embodiments, the metal pressure chamber 202 furtherincludes a sample inlet 216 that flows the liquid sample 206 from theexterior of the metal pressure chamber 202 to the liquid sample holder204 in the interior of the metal pressure chamber 202. The sample inlet216 may include a sample inlet path 218 connected to the liquid sampleholder 204 and a sample pump 220 that pumps the liquid sample 206through the sample inlet path 218 and into the liquid sample holder 204.

The sample inlet path 218 may be a rigid or flexible tubing that passesthrough the base 208 via a feedthrough 208 d and directly connects tothe liquid sample holder 204. The sample inlet path 218 may be disposedto flow the liquid sample 206 directly into the liquid sample holder 204(e.g., one end of the sample inlet path is directly connected to a wallof the liquid sample holder). In one or more embodiments, the sampleinlet path 218 is disposed to flow the liquid sample 206 onto the rockinterface 207 disposed in the liquid sample holder 204.

The sample pump 220 may be a metering pump that generates apredetermined flow rate of the liquid sample 206 in the sample inletpath 218. For example, the sample pump 220 may generate a maximum inletflow rate of 50 mL/min and a minimum inlet flow rate of 0.001 mL/min.However, depending on the reservoir conditions that are being simulated,other flow rates may be used. The sample pump 220 may be a Quizix Q6000high pressure syringe pump (Chandler Engineering). In one or moreembodiments, the sample pump 220 may include a sample storage containeror a sample preparation device (e.g., a mixer that combines an organicphase and an aqueous phase to create the liquid sample 206).

In one or more embodiments, the sample inlet 216 may further comprise aninlet valve that seals the sample inlet path 218. The inlet valve maycompletely seal the sample inlet path 218 to prevent the pressurizedenvironment in the interior of the metal pressure chamber 202 fromforcing the liquid sample 206 back into the sample pump 220.Alternatively, the inlet valve may be controlled to partially seal thesample inlet path 218 to regulate the flow rate of the liquid sample 206from the sample pump 220.

As shown in FIG. 3 , in one or more embodiments where the liquid sample206 is a brine, the sample inlet 216 may include a plurality of sampleinlet paths 218 a, 218 b, each with a corresponding sample pump 220 a,220 b that pumps a portion of the liquid sample 206 into the liquidsample holder 204. For example, a first sample inlet path 218 a may flowan aqueous phase of the liquid sample 206 into the liquid sample holder204 at a first partial flow rate. A second sample inlet path 218 b mayflow an organic phase of the liquid sample 206 into the liquid sampleholder 204 at a second partial flow rate. In other words, the liquidsample 206 may be a brine that is mixed inside of the pressure cell 200.As discussed in further detail below, an ultrasonic stage 228 mayprepare the liquid sample 206 for study by emulsifying (i.e., mixing)the organic and aqueous phases to more accurately recreate samplecompositions and liquid/liquid or liquid/solid interfaces found in thereservoir 102 (FIG. 1 ).

The metal pressure chamber 202 further includes a sample outlet 222 thatflows the liquid sample 206 from the liquid sample holder 204 in theinterior of the metal pressure chamber 202 to the exterior of the metalpressure chamber 202. The sample outlet 222 may include a sample outletpath 224 connected to the liquid sample holder 204 and a sample drain226 that removes the liquid sample 206 from the metal pressure chamber202.

The sample outlet path 224 may be a rigid or flexible tubing that passesthrough the base 208 via a feedthrough 208 d and directly connects tothe liquid sample holder 204. In one or more embodiments, the sampleoutlet path 218 may the same type of tubing as the sample inlet path218.

The sample drain 226 may be a sample storage container or a sampledisposal container. In one or more embodiments, the flow in the sampleoutlet path 224 and out of the sample drain 226 may be passivelygenerated by the sample pump 220 introducing a new portion of the liquidsample 206 into the liquid sample holder 204. Alternatively, the sampledrain 226 may also include a pump (e.g., a syringe pump) to activelyextract the liquid sample 206 from the metal pressure chamber 202.

In one or more embodiments, the sample drain 226 may further comprise anoutlet valve that seals the sample outlet path 224. The outlet valve maycompletely seal the sample outlet path 224 to prevent the pressurizedenvironment in the interior of the metal pressure chamber 202 fromforcing the liquid sample 206 out of the pressure cell. Alternatively,the outlet valve may be controlled to partially seal the sample outletpath 224 to regulate the flow of the liquid sample 206 through thesample drain 226.

The combination of the sample inlet 216 and the sample outlet 222 allowsthe composition of the liquid sample 206 in the metal pressure chamber202 to be changed in situ. In other words, the composition of the liquidsample 206 and the liquid/liquid or liquid/solid interfaces found in theliquid sample holder 204 may be actively changed and manipulated tosimulate dynamic conditions of the reservoir 102. For example, theliquid sample 206 may be diluted by introducing an aqueous injectionsolution via the sample inlet 216 to simulate the displacement of anoil/brine sample by conventional water injection recovery techniques.

The pressure cell 200 further includes an ultrasonic stage 228 that isdirectly connected to the liquid sample holder 204. The ultrasonic stage228 may be a vibrating table, a vibrating probe, an ultrasonic bath, orany other appropriate mechanism that sonicates the liquid sample 206 inthe liquid sample holder 204. In one or more embodiments, the ultrasonicstage 228 may be vibrationally isolated from the metal pressure chamber202 (e.g., to prevent misalignment of the incident light beams at thesurface of the liquid sample 206 or to prevent loosening of the sealedconnection between the base 208 and removable lid 210). For example, athermal isolation layer 240, discussed in further detail below, mayabsorb mechanical vibrations from the ultrasonic stage 228.

The ultrasonic stage 228 may be connected to a controller 232 thatprovides power and control signals to the ultrasonic stage 228. Thecontroller 232, described in further detail below with respect to FIG. 4, may control the ultrasonic stage 228 based information from the sampleinlet 216 and sample outlet 222. For example, the controller 232 maycontrol the ultrasonic stage 228 to emulsify the liquid sample 206 onlywhen the sample inlet 216 and sample outlet 222 have completed settingor altering of the composition of the liquid sample 206. In one or moreembodiments, the ultrasonic stage 228 may emulsify an aqueous phase andan organic phase of the liquid sample 206 for 30 seconds to generate abrine, an oil/water emulsion, or a nano-sized oil emulsion.

The pressure cell 200 further includes a chamber pump 230 that isconnected to, and pressurizes, the interior of the metal pressurechamber 202. The chamber pump 230 may be a vacuum pump, a compressor, apneumatic compressor, a hydraulic compressor, any other appropriatemechanism that generates a pressurized environment in the interior ofthe metal pressure chamber 202, or any combination thereof. In one ormore embodiments, the chamber pump 230 may be vibrationally isolatedfrom the metal pressure chamber 202 (e.g., to prevent misalignment ofthe incident light beams at the surface of the liquid sample 206 or toprevent loosening of the sealed connection between the base 208 andremovable lid 210). For example, the feedthrough 208 d and/or the tubingthat connects the chamber pump 230 and the metal pressure chamber 202may absorb mechanical vibrations from the chamber pump 230.

The pressure range of the chamber pump 230 may be between ambientatmospheric pressure (e.g., around 14.7 psi) to approximately 3000 psi.However, as conditions in a reservoir 102 (FIG. 1 ) may vary accordingto many parameters (e.g., depth, geographic location, rock composition),the pressure range of the chamber pump 230 is not limited to thisapproximate value and pressures greater than 3000 psi may beimplemented. In one or more embodiments, the chamber pump 230 mayfurther comprise a vacuum pump that evacuates the metal pressure chamber202 (e.g., to outgas components).

The chamber pump 230 may be connected to a controller 232 that providespower and control signals to the chamber pump 230. The controller 232,described in further detail below with respect to FIG. 4 , may controlthe chamber pump 230 based upon a pressure gauge 234 that measures apressure of the interior of the metal pressure chamber 202. Furthermore,the controller 232 may also control a control valve 236 that seals themetal pressure chamber 202 from the chamber pump 230. Furthermore, thecontroller 232 may open the control valve 236 to release pressure fromthe interior of the metal pressure chamber 202. In other words, thecontroller 232 may control the chamber pump 230 and the control valve236 to control (e.g., increase, decrease, maintain) the pressure in themetal pressure chamber 202.

The pressure cell 200 further includes a heating stage 238 (e.g., aheating element) that heats the liquid sample 206. In one or moreembodiments, the heating stage 238 is an electric heater (e.g.,electrical joule heater, ohmic heater), however any appropriate heatingelement may be used to heat the liquid sample 206. The heating stage 238may be directly connected to the liquid sample holder 204. In someembodiments, a thermal isolation layer 240 may be disposed on theheating stage 238 (e.g., between the heating stage 238 and the metalpressure chamber 202) to thermally isolate the heating stage 238 fromthe metal pressure chamber (i.e., prevent the metal pressure chamber 202from unnecessarily heating during operation). The thermal isolationlayer 240 may be made of mica. Alternatively, the thermal insulationlayer may a ceramic that includes one or more of aluminum oxide (Al₂O₃),silica (SiO₂), magnesium oxide (MgO), or any combination thereof.

The temperature range of the heating stage 238 may be between 25-100 C.°to simulate the temperatures of the reservoir 102. However, asconditions in a reservoir 102 (FIG. 1 ) may vary according to manyparameters (e.g., depth, geographic location, rock composition), thetemperature range of the heating stage 238 is not limited to this rangeand temperatures greater than 100 C.° may be implemented.

The heating stage 238 may be connected to a temperature controller 242disposed outside of the metal pressure chamber 202. The temperaturecontroller 242 may be a hardware or software component of the controller232 or may be a distinct controller apparatus. The temperaturecontroller 242 provides power and control signals to the heating stage238 through one or more feedthroughs 208 d in the metal pressure chamber202. The temperature controller 242 may control the heating stage 238based on a temperature of the liquid sample 206 that is measured by athermocouple 244 connected to the liquid sample holder 204.

In one or more embodiments, the pressure cell 200 further includes apositioning stage 246 that controls a position of a surface of theliquid sample 206. The positioning stage 246 may include one or moreactuators (e.g., an electric actuator, a pneumatic actuator, a hydraulicactuator, a piezoelectric actuator, or any combination thereof) thattranslates the base 208 or the liquid sample holder 204 in one or moredimensions (e.g., a vertical direction) to align the surface of theliquid sample 206 with the incident light beams. The positioning stage246 may automatically position the surface of the liquid sample 206based on optical feedback from the surface of the liquid sample 206, asdescribed in further detail below with respect to FIG. 5 . Thepositioning stage 246 may be controlled by the controller 232.

In one or more embodiments, the positioning stage 246 may be disposed onan interior surface of base 208, as shown in FIG. 2 . The positioningstage 246 may translate the liquid sample holder 204, the heating stage238, and the ultrasonic stage 228 to align the surface of the liquidsample with respect to the incident light. The positioning stage 246 maybe separated from the heating stage 238 by the thermal insulation layer224 that prevents the positioning stage 246 from unnecessarily heatingup during operation.

In another embodiment, as shown in FIG. 3 , the positioning stage 246may be disposed exteriorly to the metal pressure chamber 202 while theheating stage 238 is disposed in the interior of the metal pressurechamber 202. The positioning stage 246 may translate the metal pressurechamber 202 and the entire contents thereof to align the surface of theliquid sample 206 with respect to the incident light. An externalpositioning stage 246 advantageously reduces the number of feedthroughs208 d and the possibility of leaks from the metal pressure chamber 202.

FIG. 4 shows a schematic of a controller 232 according to one or moreembodiments. As discussed above, in one or more embodiments, thecontroller 232 may control the chamber pump 230, the heating stage 238,and the ultrasonic stage 228 to control a pressure of the interior ofthe metal pressure chamber 202, a temperature of the liquid sample 206,and an emulsification of the liquid sample 206, respectively. Thecontroller 232 may be implemented on virtually any type of computingsystem, regardless of the platform being used. For example, thecomputing system may be one or more mobile devices (e.g., laptopcomputer, smart phone, personal digital assistant, tablet computer, orother mobile device), desktop computers, servers, blades in a serverchassis, or any other type of computing device or devices that includesat least the minimum processing power, memory, and input and outputdevice(s) to perform one or more embodiments disclosed herein. Forexample, as shown in FIG. 4 the controller 232 may include one or morecomputer processor(s) 402, associated memory 404 (e.g., random accessmemory (RAM), cache memory, flash memory), one or more storage device(s)406 (e.g., a hard disk, an optical drive such as a compact disk (CD)drive or digital versatile disk (DVD) drive, a flash memory stick), andnumerous other elements and functionalities. The computer processor(s)402 may be an integrated circuit for processing instructions. Forexample, the computer processor(s) may be one or more cores, ormicro-cores of a processor.

The controller 232 may also include one or more input device(s) 408,such as a pressure gauge 234, thermocouple 244, SFG microscope 500(discussed in further detail with respect to FIG. 5 ), camera, imager,touchscreen, keyboard, mouse, microphone, touchpad, electronic pen, orany other type of input device. Further, the controller 232 may includeone or more output device(s) 410, such as a screen (e.g., a liquidcrystal display (LCD), a plasma display, touchscreen, cathode ray tube(CRT) monitor, or other display device), a printer, external storage, orany other output device. One or more of the output device(s) may be thesame or different from the input device(s). The controller 232 may beconnected to a network 412 (e.g., a local area network (LAN), a widearea network (WAN) such as the Internet, mobile network, or any othertype of network) via a network interface connection (not shown). Theinput and output device(s) may be locally or remotely (e.g., via thenetwork 412) connected to the computer processor(s) 402, memory 404, andstorage device(s) 406. Many different types of computing systems exist,and the aforementioned input and output device(s) 408, 410 may takeother forms.

Further, one or more elements of the controller 232 may be located at aremote location and be connected to the other elements over a network412. Further, one or more embodiments may be implemented on adistributed system having a plurality of nodes, where each portion ofthe embodiment may be located on a different node within the distributedsystem. In one embodiment, the node corresponds to a distinct computingdevice. In other embodiments, the node may correspond to a computerprocessor with associated physical memory. In yet other embodiments, thenode may correspond to a computer processor or micro-core of a computerprocessor with shared memory and/or resources.

FIG. 5 shows a system 500 for performing SFG spectroscopy according toone or more embodiments. A system 500 for performing SFG spectroscopymay include a pressure cell 200, as previously described with respect tothe embodiments of FIGS. 2-3 , and an SFG microscope 501. The SFGmicroscope 501 may be an SFG vibrational spectrometer (Ekspla), forexample.

The SFG microscope 501 includes a first light source 502 that generateslight of the first variable frequency f₁. The range of the firstvariable frequency f₁ may correspond to the vibrational energy of amolecule in the liquid sample (e.g., corresponds to an infraredwavelength of light). The first light source 502 may be disposed tofocus the light of the first variable frequency f₁ on the surface of theliquid sample 206 with an incidence angle of 60° with respect to asurface normal vector. In one or more embodiments, the first lightsource 502 is pulsed laser source with a pulse energy of 2.7-35 mJ and apulse duration of 28+/−10 picoseconds. For example, the first lightsource 502 may comprise a PL2231-50 picosecond laser centered at 1064 nm(Ekspla) that feeds into a SFGH500 multichannel beam delivery unit(Ekspla) that feeds a PG501-DFGx optical parametric generator (Ekspla)that outputs a variable IR wavelength ranging of 2300-16000 nm. Thefirst light source may further include a visible laser to aid infocusing the light of the variable frequency f₁.

The SFG microscope 501 further includes a second light source 504 thatgenerates light of the second frequency f₂. The second frequency f₂ isdifferent from the first variable frequency f₁ and may correspond to avirtual energy state (e.g., may correspond to a visible wavelength oflight). The second light source 504 may be disposed to focus the lightof the second frequency f₂ on the surface of the liquid sample 206 withan incidence angle of 55° with respect to a surface normal vector. Inone or more embodiments, the second light source 504 is pulsed lasersource with a pulse energy of 2.7-35 mJ and a pulse duration of 28+/−10picoseconds. For example, the second light source 502 may be a secondoutput of the PG501-DFGx optical parametric generator (Ekspla) thatoutputs a fixed 532 nm wavelength.

However, the present disclosure is not limited to this configuration andany appropriate light sources for generating an SFG signal (i.e., lightof the third frequency f₃ that is the sum of the first and secondfrequencies f₁, f₂) may be used. The first and second light sources 502,504 are configured to spatially and temporally overlap the first andsecond light beams at the surface of the liquid sample 206 to generatethe SFG signal. The SFG signal may be a pulsed signal with a pulseenergy of 0.52-5.3 mJ and a pulse duration of 28+/−10 picoseconds.

The SFG microscope 501 further comprises a detector 506 that detectslight. The detector 506 is offset from the light sources 502, 504 of theSFG microscope 501 to collect the SFG signal emitted from the liquidsample 206. The detector 506 may include additional optical elements(e.g., lens, spatial filter, frequency filter, spectrometer, powermeter) to control, measure, and manipulate the detected light. Forexample, in one or more embodiments where multiple vibrationalfrequencies are probed simultaneously, the detector 506 may be amonochromator that collects and spectrally separates differentfrequencies of light in the collected signal.

In one or more embodiments, the SFG microscope 501 may further includeadditional optical elements (e.g., mirror, lens, spatial filter,frequency filter, delay line, spectrometer, power meter) to control,measure, and manipulate the emitted and detected light.

In one or more embodiments, the SFG microscope 501 may be controlled bythe controller 232. For example, the controller 232 may instruct the SFGmicroscope 501 to begin data acquisition once the chamber pump 230 haspressurized the metal pressure chamber 202 to a predetermined pressure,the heating stage 238 has heated the liquid sample 206 to apredetermined temperature measured by the thermocouple 228, and theultrasonic stage 228 has emulsified the liquid sample 206 to apredetermined degree of emulsification.

In one or more embodiments, the controller 232 may halt data acquisitionwhile the sample inlet 216 and sample outlet 222 control the compositionof the liquid sample 206 in the liquid sample holder 204. Specifically,adjusting the flow rate of the liquid sample 206 or adding/removing aquantity of the liquid sample 206 may modify the position of the surfaceof the liquid sample 206 and disrupt the spatial overlap of the firstand second light beams at the surface. Furthermore, the controller 232may halt data acquisition while the liquid sample 206 is beingemulsified because the surface of the liquid sample 206, and thus thespatial overlap of the first and second light beams, may be disrupted bythe ultrasonic stage 228 process.

Furthermore, the controller 232 may use one or more of the first andsecond light sources 502, 504 to illuminate the liquid sample 206 toalign the liquid sample holder 204 using the positioning stage 246. Forexample, a portion of the light emitted by the first light source 502(e.g., the light of the first variable frequency f₁ or the visiblealignment laser) may reflect off of the surface of the liquid sample 206and be detected by the detector 506 or a second detector (not shown) ofthe SFG microscope 501. Alternatively, the detector 506 may detect theSFG signal. Based on a position or an intensity of the detected signal,the controller 232 controls the positioning stage 246 to align theliquid sample 206 with the convergence point of the spatially andtemporally overlapped first and second light beams.

FIGS. 6A and 6B show a flowchart according to one or more embodiments.The flowchart depicts a method for performing SFG spectroscopy that maybe performed using the pressure cell 200 described above in reference toFIGS. 2, 3, and 5 . In one or more embodiments, one or more of the stepsshown in FIGS. 6A and 6B may be combined, omitted, repeated, and/orperformed in a different order than the order shown in FIGS. 6A and 6B.Accordingly, the scope of the present disclosure should not beconsidered limited to the specific arrangement of steps shown in FIGS.6A and 6B.

At 600, a rock interface 207 is loaded into a liquid sample holder 204disposed inside of a metal pressure chamber 202 that includes a base 208and a removable lid 210. The rock interface 207 may be a calcite rocksample or any other appropriate material that may simulate liquid/solidinteractions or liquid/solid interfaces that occurring in a reservoir102 (FIG. 1 ).

At 602, the removable lid 210 is sealed onto the base 208 to seal theliquid sample holder 204 in an interior of the metal pressure chamber202. The seal may be formed by screwing, clipping, mechanical fastening(e.g., with bolts, screws) the removable lid 210 onto the base 208.However, the removable lid 210 may be sealed to the base 208 by anyappropriate means that provides a seal to contain the pressure of thesimulated reservoir environment. In one or more embodiments, a seal 212(e.g., elastomeric O-ring, copper gasket, or other seal) may be disposedbetween the base 208 and the removable lid 210 to seal the metalpressure chamber 202.

At 604, a liquid sample 206 is flowed from an exterior of the metalpressure chamber 202, through a sample inlet 216, to the liquid sampleholder 204. In one or more embodiments, the liquid sample 206 may be abrine comprising a mixture of an aqueous phase and an organic phase thatis flowed through a single sample inlet path 218. The flow of the liquidsample 206 in the sample inlet path 218 may be generated by a samplepump 220.

In another embodiment, the aqueous phase and organic phase of the liquidsample 206 may be separate liquids that are flowed into the liquidsample holder 204 by separate sample inlet paths 218 a, 218 b. Therelative proportions of the aqueous and organic phases introduced intothe liquid sample holder 204 may be controlled by separate sample pumps220 a, 220 b that are connected to the corresponding sample inlet paths218 a, 218 b.

At 606, an ultrasonic stage 228 emulsifies the liquid sample 206. In oneor more embodiments including a mixture of an aqueous phase and anorganic phase (e.g., a brine) as the liquid sample 206, the ultrasonicstage 228 may sonicate the liquid sample 206 to emulsify the two phases.

At 608, a heating stage 238 heats the liquid sample 206 to a simulatedreservoir temperature. In one or more embodiments, the temperature ofthe liquid sample 206 is raised to approximately 90-100 C°. However, asdiscussed above, the present disclosure is not limited to thistemperature range because conditions of a reservoir 102 may varyaccording to many parameters (e.g., depth, geographic location, rockcomposition). The temperature of the liquid sample 206 may be monitoredby a thermocouple 244 that is connected to the liquid sample holder 204.The thermocouple 244 may send temperature information to a temperaturecontroller 242, or alternatively a controller 232, that sends power andcontrol signals to the heating stage 238.

At 610, a chamber pump 230 connected to the interior of the metalpressure chamber 202 increases the pressure inside the metal pressurechamber 202 to a simulated reservoir pressure. In one or moreembodiments, the pressure of the liquid sample 206 is raised toapproximately 3000 psi. However, as discussed above, the presentdisclosure is not limited to this approximate pressure value becauseconditions of a reservoir 102 may vary according to many parameters(e.g., depth, geographic location, rock composition). The pressure ofthe interior of the metal pressure chamber 202 may be monitored by apressure gauge 234. The pressure gauge 234 may send pressure informationto the controller 232 that sends power and control signals to thechamber pump 230. Furthermore, the controller 232 may control a controlvalve 236 to seal the metal pressure chamber 202 from the chamber pump230 or release pressure from the interior of the metal pressure chamber202.

At 612, a surface of the liquid sample 206 is illuminated with light ofa first variable frequency f₁ and light of a second frequency f₂ througha window 214 of the metal pressure chamber 202. The incident light beamsof the first and second frequencies f₁, f₂ are spatially and temporallyoverlapped at the surface of the liquid sample 206 to generate an SFGsignal (i.e., light of the third frequency f₃ that is the sum of thefirst and second frequencies f₁, f₂).

In one or more embodiments, a positioning stage 246 may translate thesurface of the liquid sample 206 to align the surface of the liquidsample 206 with the incident first and second light beams. Thepositioning stage 246 may automatically position the surface of theliquid sample 206 based on a reflected signal from the surface of theliquid sample 206 (e.g., alignment with the surface of the liquid sample206 is achieved when the reflected signal exceeds a predeterminedthreshold or reaches a predetermined position on a detector 506).Alternatively, the positioning stage 246 may automatically position thesurface of the liquid sample 206 based on an intensity of the generatedSFG signal (e.g., alignment with the surface of the liquid sample 206 isachieved when the SFG signal is maximized or exceeds a predeterminedthreshold). In yet another embodiment, the positioning stage 246 may becontrolled manually.

At 614, the SFG signal comprising light of a third frequency f₃ iscollected from the surface of the liquid sample 206 for analysis.

At 616, the liquid sample 206 is flowed from the liquid sample holder204, through a sample outlet 222, to the exterior of the metal pressurechamber 202. In one or more embodiments, the liquid sample 206 that isremoved from the metal pressure chamber may be replace by a new liquidsample 206 from the sample inlet path 218.

In other words, in one or more embodiments, the composition of theliquid sample 206 may be altered in situ by flowing different solutionsor different proportions of the aqueous phase and organic phase into theliquid sample holder 204 and removing the liquid sample 206 that hasalready been studied. Thus, the liquid sample 206 may be characterizedin both static and dynamic reservoir compositions (e.g., stable live oilcompositions or dynamically changing compositions that may modeldisplacement of hydrocarbons by an injection fluid).

In one or more embodiments, In one or more embodiments, the heatingstage 238 and the chamber pump 230 may dynamically change thetemperature and pressure inside the metal pressure chamber 202 duringacquisition of the SFG signal. For example, the controller 232 may rampthe temperature or pressure to different values in response to datacollected from the pressure gauge 234, the control valve 236, thethermocouple 244, the detector 706, or any combination thereof. Thus,the liquid sample 206 may be characterized in both static and dynamicreservoir environments (e.g., stable temperature and pressure conditionsor dynamically changing temperature and/or pressure conditions).

In one or more embodiments, the first variable frequency f₁ may becontinuously or discretely changed to obtain a spectrum of SFG signalsfrom the liquid sample 206. In another embodiment, first variablefrequency f₁ may be a spectrally broadband frequency range that includesa plurality of frequencies. Accordingly, a spectrum of SFG signals fromthe liquid sample 206 may be obtain at one time.

Software instructions in the form of computer readable program code toperform embodiments of the present disclosure may be stored, in whole orin part, temporarily or permanently, on a non-transitory computerreadable medium such as a CD, DVD, storage device, a diskette, a tape,flash memory, physical memory, or any other computer readable storagemedium. Specifically, the software instructions may correspond tocomputer readable program code that when executed by a processor(s), isconfigured to perform embodiments disclosed herein.

One or more of the embodiments disclosed herein may have one or more ofthe following advantages and improvements over conventional SFGspectroscopy techniques: simulating reservoir conditions (e.g., highpressure, high temperature environments); simulating reservoirinteractions for study in a controlled environment; SFG spectroscopyunder static and dynamic temperature and/or pressure conditions; SFGspectroscopy with dynamic sample compositions to analyze more accurateliquid/liquid and liquid/solid interfaces that occur in hydrocarbonreservoirs. One or more of the above advantages may improve a user'sunderstanding of the chemical and molecular structures and interfacesthat occur in a reservoir and improve the effectiveness of hydrocarbonrecovery techniques.

Although the disclosure has been described with respect to only alimited number of embodiments, those skilled in the art, having benefitof this disclosure, will appreciate that various other embodiments maybe devised without departing from the scope of the present disclosure.Accordingly, the scope of the disclosure should be limited only by theattached claims.

What is claimed is:
 1. A system for sum frequency generationspectroscopy, the system comprising: a pressure cell comprising: a metalpressure chamber including: a liquid sample holder that retains a liquidsample; a removable lid that seals against a base to enclose the liquidsample holder in an interior of the metal pressure chamber; a window inthe removable lid that allows the liquid sample to be optically accessedfrom an exterior of the metal pressure chamber; a sample inlet thatflows the liquid sample from the exterior of the metal pressure chamberto the liquid sample holder in the interior of the metal pressurechamber at a predetermined flow rate; and a sample outlet that flows theliquid sample from the liquid sample holder to the exterior of the metalpressure chamber; a heating stage, disposed in the interior of the metalpressure chamber, that heats the liquid sample; an ultrasonic stage,disposed in the interior of the metal pressure chamber, that emulsifiesthe liquid sample; a chamber pump, connected to the interior of themetal pressure chamber, that pressurizes the interior of the metalpressure chamber; and a controller that controls the chamber pump, theultrasonic stage, and the heating stage to control a pressure of theinterior of the metal pressure chamber, an emulsification of the liquidsample, and a temperature of the liquid sample, respectively; and a sumfrequency generation microscope comprising: a first light source thatgenerates light of a first variable frequency; a second light sourcethat generates light of a second frequency; and a detector that detectslight.
 2. The system according to claim 1, wherein the sample inletcomprises: a sample inlet path connected to the liquid sample holder;and a sample pump that pumps the liquid sample through the sample inletpath and into the liquid sample holder, wherein the controller controlsthe predetermined flow rate of the sample pump.
 3. The system accordingto claim 1, wherein the sample inlet comprises a plurality of sampleinlet paths, and each of the plurality of sample inlet paths isconnected to a corresponding sample pump that pumps a portion of theliquid sample into the liquid sample holder.
 4. The system according toclaim 3, wherein a first sample inlet path of the plurality of sampleinlet paths flows an aqueous phase of the liquid sample into the liquidsample holder, a second sample inlet path of the plurality of sampleinlet paths flows an organic phase of the liquid sample into the liquidsample holder, and the ultrasonic stage emulsifies the liquid sample tocreate a brine from the aqueous and organic phases.
 5. The systemaccording to claim 1, wherein the heating stage and the ultrasonic stageare directly connected to the liquid sample holder.
 6. The systemaccording to claim 5, further comprising a thermal insulation layer thatthermally isolates the heating stage from the metal pressure chamber. 7.The system according to claim 1, wherein the pressure cell furthercomprises: a pressure gauge that measures the pressure of the interiorof the metal pressure chamber; a control valve that seals the interiorof the metal pressure chamber from the chamber pump; a thermocouple thatmeasures the temperature of the liquid sample; and an inlet valve and anoutlet valve that seal the sample inlet path and sample outlet path,respectively, wherein the controller controls the chamber pump, thecontrol valve, the inlet valve, and the outlet valve based on thepressure measured by the pressure gauge, and the controller controls theheating stage based on the temperature measured by the thermocouple. 8.The system according to claim 1, wherein the liquid sample holderfurther comprises a rock interface that interacts with the liquidsample.
 9. The system according to claim 1, further comprising apositioning stage that automatically positions a surface of the liquidsample based on optical feedback from the surface of the liquid sample.10. A method of performing sum frequency generation spectroscopy in apressure cell, the method comprising: sealing a liquid sample holder inan interior of a metal pressure chamber of the pressure cell, whereinthe metal pressure chamber comprises a base and a removable lid; flowinga liquid sample from an exterior of the metal pressure chamber, thorougha sample inlet, to the liquid sample holder in the interior of the metalpressure chamber at a predetermined flow rate; emulsifying the liquidsample with an ultrasonic stage; heating the liquid sample with aheating stage; pressurizing the interior of the metal pressure chamberwith a chamber pump that is connected to the interior of the metalpressure chamber; illuminating a surface of the liquid sample with lightof a first variable frequency and light of a second frequency through awindow of the metal pressure chamber; collecting, through the window,light of a third frequency from the surface of the liquid sample,wherein the third frequency is the sum of the first variable frequencyand the second frequency; and flowing the liquid sample from the liquidsample holder, through a sample outlet, to the exterior of the metalpressure chamber.
 11. The method according to claim 10, furthercomprising: pumping the liquid sample through a sample inlet path with asample pump, wherein the sample inlet path is connected to the liquidsample holder.
 12. The method according to claim 10, further comprising:pumping a plurality of portions of the liquid sample through a pluralityof sample inlet paths of the sample inlet and into the liquid sampleholder, wherein each sample inlet path of the plurality of sample inletpaths includes a corresponding sample pump.
 13. The method according toclaim 12, further comprising: pumping an aqueous phase of the liquidsample into the liquid sample holder from a first sample inlet path ofthe plurality of sample inlet paths; and pumping an organic phase of theliquid sample into the liquid sample holder from a second inlet path ofthe plurality of sample inlet paths, wherein emulsifying the liquidsample with the ultrasonic stage creates a brine from the aqueous andorganic phases.
 14. The method according to claim 10, further comprisingdirectly connecting the heating stage and the ultrasonic stage to theliquid sample holder.
 15. The method according to claim 10, furthercomprising: measuring a pressure of the interior of the metal pressurechamber with a pressure gauge; and measuring a temperature of the liquidsample with a thermocouple; controlling the chamber pump, a controlvalve that seals the interior of the metal pressure chamber from thechamber pump, an inlet valve that seals the sample inlet path, and anoutlet valve that seals the sample outlet path based on the pressuremeasured by the pressure gauge, and controlling the heating stage basedon the temperature measured by the thermocouple.
 16. The methodaccording to claim 10, further comprising: positioning the surface ofthe liquid sample to align the surface of the liquid sample with thelight of the first variable frequency and the light of the secondfrequency.
 17. The method according to claim 16, wherein the positioningcomprises automatically positioning the surface of the liquid samplebased on a reflected signal from the surface of the liquid sample. 18.The method according to claim 16, wherein the positioning comprisesautomatically positioning the surface of the liquid sample based on anintensity of a sum frequency generation signal.